US gas major Chevron has made another large discovery off Western Australia, adding more resources that could feed an expansion of the $43 billion Gorgon liquefied natural gas project.

The Satyr-2 well was found about 39 metres of net gas “pay", in a licence area about 120 kilometres north-west of the Barrow Island site where Chevron and partners ExxonMobil and Shell are building the 15 million tonnes per year Gorgon plant, California-based Chevron said in a statement.

Chevron, ExxonMobil and Shell have already confirmed about 40 trillion cubic feet of gas resources for Gorgon, but are still exploring for more discoveries to underpin an expansion of the project.

They are hoping to commit to engineering and design work on a fourth LNG train at Barrow Island by the year end. The first of the three trains already under construction at the site is due to start production in 2014.

ExxonMobil and Shell also own stakes in the WA-374-P permit where the latest discovery was made.